Chemical mechanical polishing (CMP) is one of several processes used in the manufacture of semiconductor chips. CMP is generally used to polish the surface of an unprocessed or partially processed work piece to provide a substantially smooth surface suitable for the application of subsequent fabrication processes, such as photoresist coating and pattern definition. The CMP process can be used in various instances during the manufacture of an integrated circuit, for example, at the beginning of the manufacturing process, or after a metallization process. During CMP, a work piece surface is generally polished by contacting the work piece to a polishing surface and moving at least one relative to the other. Optionally, a polishing compound, such as an acidic or basic slurry, can be imparted to the work piece during polishing.
After a polishing process, undesirable contaminants from the polishing slurry and particles of the removed material may be present on the work piece. These contaminants and particles cause corrosion of metals and/or lead to undesirable local conductive and dielectric properties of the processed layers. Defective work pieces may result, which ultimately may yield inoperable devices. Thus, after the polishing process, the work piece may need to undergo cleaning and drying before further processing can take place on the work piece.
Typically, a work piece is buffed with a soft pad, such as a Politex pad from Rohm & Haas Equipment Manufacturers, Inc., using deionized water or abrasive slurry to smooth out surface non-uniformities. Then, the work piece is cleaned with either an acidic or a basic cleaning composition. Conventional cleaning methods may employ the use of polishing or scrubbing brushes to deliver a cleaning composition the surface of the work piece. Other conventional cleaning techniques include spraying a cleaning composition on to the work piece. Yet other cleaning techniques include dipping the work piece into a bath containing a cleaning composition and using a transducer to create sonic waves that travel through the cleaning composition to the work piece surface to impart energy useful in cleaning and dislodging the unwanted particles from the work piece.
Although the above-mentioned methods may be adequate for cleaning work pieces used in the manufacture of larger electronic devices, they have not been as useful for cleaning microelectronic devices of nanometer levels. As microelectronic devices become increasingly smaller, work piece defect count becomes more important to the manufacture of operable devices. It has been found that prior methods of cleaning may not remove a sufficient number of particles from the work piece to yield a work piece having a defect count that is low enough to be useful for the manufacture of operable microelectronic devices.
Accordingly, it is desirable to provide an improved method and apparatus for cleaning a semiconductor work piece. Moreover, a method and apparatus is desirable that is capable of decreasing the number of defects on the work piece. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.